Drug specific cytotoxic T-cells in the skin lesions of a patient with toxic epidermal necrolysis

Management of Toxic Epidermal Necrolysis with Plasmapheresis and Cyclosporine A: Our 10 Years' Experience

Background:

The management of toxic epidermal necrolysis (TEN) is controversial and there is no uniform strategy.

Objective:

To share our 10 years’ experience in treating severe TEN with a novel protocol based on the association of cyclosporine A and plasmapheresis.

Methods:

In this case series, we retrospectively collected and assessed the 12 cases of severe TEN treated from 2005 to 2015 at the Burn Unit of the University of Bari Policlinico hospital.

Results:

Average body surface area was 77; average SCORETEN was 4.3. The 12 patients had been treated with culprit drug withdrawal, systemic corticosteroids, and/or cyclosporine A with no response. The protocol was successfully administered in all 12 cases. Average time to response from protocol start was 4.9 days. Average time to remission from protocol start was 22 days; average hospital stay at our unit was 24.8 days. Four patients developed severe complications; 1 patient died. No complications linked to the protocol therapeutic measures were observed. The relatively small number of cases given the rarity of the condition is a limitation of this report.

Conclusion:

Our protocol based on the association of cyclosporine A and plasmapheresis is safe and efficacious in treating severe TEN.

Adverse Medication Reactions

Cutaneous adverse drug reactions (ADRs) are among the most frequent adverse reactions in patients receiving drug therapy. They have a broad spectrum of clinical manifestations, are caused by various drugs, and result from different pathophysiological mechanisms. Hence, their diagnosis and management is challenging.

Severe cutaneous ADRs comprise a group of diseases with major morbidity and mortality, reaching 30 % mortality rate in cases of Toxic Epidermal Necrolysis.

This chapter covers the terminology, epidemiology, pathogenesis and classification of cutaneous ADR, describes the severe cutaneous ADRs and the clinical and laboratory approach to the patient with cutaneous ADR and presents the translation of laboratory-based discoveries on the genetic predisposition and pathogenesis of cutaneous ADRs to clinical management guidelines.

Chronic Ocular Complications of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: The Role of Systemic Immunomodulatory Therapy

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, but potentially blinding diseases that affect the skin and mucous membranes. Although the cutaneous manifestations tend to be self-limited and resolve without sequelae, the chronic ocular complications associated with SJS/TEN can persist despite local therapy. Poor understanding of the underlying pathophysiology and lack of a standardized clinical approach have resulted in a paucity of data in regards to suitable treatment options. Inflammatory cellular infiltration and elevated levels of ocular surface cytokines in the conjunctival specimens of affected patients give credence to an underlying immunogenic etiology. Furthermore, the presence of ongoing ocular surface inflammation and progressive conjunctival fibrosis in the absence of exogenous aggravating factors suggest a possible role for systemic immunomodulatory therapy (IMT). We review in detail the proposed immunogenesis underlying chronic ocular SJS/TEN and the possible utility of systemic IMT.

Immunologic Mediators in Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are a spectrum of T-cell mediated immune disorders. While the contributory mechanisms leading to the apoptosis of epidermal cells in SJS/TEN remain unproven, the keratinocyte apoptosis seen in SJS/TEN is thought to occur through the T-cell mediated Fas-Fas ligand (FasL), perforin/granzyme B, and other immune mediators. Most recently, emphasis has been placed on the granulysin pathway as being the primary mediator of apoptosis and widespread epidermal necrosis in SJS/TEN. This article aims to review the proposed mechanisms by which these pathways work and the immunomodulatory therapies that have been developed in an attempt to target them.

Continuous venovenous hemofiltration combined with hemoperfusion for toxic epidermal necrolysis: a retrospective cohort study

AIM

The current treatments of toxic epidermal necrolysis (TEN) are limited to the discontinuation of a suspect medication and supportive measures. We conducted a retrospective study to evaluate the efficacy of adding continuous venovenous hemofiltration (CVVH) and hemoperfusion (HP) to the conventional treatment for TEN.

METHODS

TEN patients who were admitted to our center between January 2008 and May 2016 were considered as candidates. The included patients were divided into the CVVH&HP group (n = 34) and the conventional group (n = 34) according to their accepted therapies during hospital stay.

RESULTS

The patients in the conventional group had a significantly reduced 28-day survival proportion compared with patients in the CVVH&HP group (73.5 versus 91.2%, p = .047). The adjusted results demonstrated that the conventional group had a significantly higher risk of 28-day mortality as well. Moreover, patients in the CVVH&HP group were associated with significantly shorter hospital stay, rash, fever, and antibiotic durations. However, the addition of CVVH&HP to conventional treatment did not significantly increase the in-hospital cost.

CONCLUSIONS

In conclusion, CVVH&HP might be a safe and effective adjuvant therapy for TEN. Further well-designed studies are warranted to obtain robust evidence.

Epidermal necrolysis: 60 years of errors and advances

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare conditions characterized by extensive epidermal detachment and mucositis. Both are associated with a high mortality rate and significant long-term morbidity. Since the initial report introducing the term TEN in 1956, diagnosis of the condition has been fraught with difficulties that continue to exist today. The terms 'erythema multiforme major' (EMM) and SJS, and their relationship to TEN have also been confusing to clinicians. It is now recognized that EMM is a different entity from SJS and TEN in terms of demographics, causality and severity. SJS and TEN represent a continuum of disease, and differ only by the extent of epidermal detachment and therefore severity. The term 'epidermal necrolysis' (EN) is used in this article to describe the spectrum of disease that includes SJS and TEN. Important advances in understanding the pathomechanism and treatment of EN have been made over the years. These include the recognition of human leucocyte antigen (HLA) associations (e.g. HLA-B*1502 with carbamazepine-induced TEN) and understanding of the pathogenic roles of drug-specific cytotoxic T cells and granulysin. It was previously believed that widespread keratinocyte death in EN is predominantly mediated by soluble Fas-ligand and that intravenous immunoglobulin therapy is useful in blocking this mechanism with resultant survival benefits. Further studies have since proven these theories to be incorrect. This short review describes the key advances in the terminology, classification, causality and treatment of EN, and identifies future priorities and challenges in the understanding and management of this condition.

Drug induced exfoliative dermatitis: state of the art

Drug induced exfoliative dermatitis (ED) are a group of rare and severe drug hypersensitivity reactions (DHR) involving skin and usually occurring from days to several weeks after drug exposure. Erythema multiforme (EM), Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are the main clinical presentations of drug induced ED. Overall, T cells are the central player of these immune-mediated drug reactions. Here we provide a systematic review on frequency, risk factors, pathogenesis, clinical features and management of patients with drug induced ED.

Severe cutaneous adverse drug reactions

The clinical manifestations of drug eruptions can range from mild maculopapular exanthema to severe cutaneous adverse drug reactions (SCAR), including drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) which are rare but occasionally fatal. Some pathogens may induce skin reactions mimicking SCAR. There are several models to explain the interaction of human leukocyte antigen (HLA), drug and T-cell receptor (TCR): (i) the "hapten/prohapten" theory; (ii) the "p-i concept"; (iii) the "altered peptide repertoire"; and (iv) the "altered TCR repertoire". The checkpoints of molecular mechanisms of SCAR include specific drug antigens interacting with the specific HLA loci (e.g. HLA-B*15:02 for carbamazepine-induced SJS/TEN and HLA-B*58:01 for allopurinol-induced SCAR), involvement of specific TCR, induction of T-cell-mediated responses (e.g. granulysin, Fas ligand, perforin/granzyme B and T-helper 1/2-associated cytokines) and cell death mechanism (e.g. miR-18a-5p-induced apoptosis; annexin A1 and formyl peptide receptor 1-induced necroptosis in keratinocytes). In addition to immune mechanism, metabolism has been found to play a role in the pathogenesis of SCAR, such as recent findings of strong association of CYP2C9*3 with phenytoin-induced SCAR and impaired renal function with allopurinol SCAR. With a better understanding of the mechanisms, effective therapeutics and prevention for SCAR can be improved.

Candidate HLA genes for prediction of co-trimoxazole-induced severe cutaneous reactions

BACKGROUND

Co-trimoxazole is a sulfonamide-containing antibiotic that is effective in the treatment of several infections and for prophylaxis of Pneumocystis jiroveci pneumonia. This drug has been reported as a common culprit drug for the Stevens-Johnson syndrome (SJS) and for toxic epidermal necrolysis (TEN). Human leukocyte antigens (HLAs) play a key role in the immunopathogenesis of severe cutaneous reactions induced by several drugs. This study investigated the association between the HLA class I and HLA-DRB1 polymorphisms and co-trimoxazole-induced SJS/TEN in a Thai population.

METHODS

Forty-three patients with co-trimoxazole-induced SJS/TEN and 91 co-trimoxazole-tolerant patients were enrolled in the study. HLA class I and HLA-DRB1 were genotyped using the reverse sequence-specific oligonucleotide probe method.

RESULTS

The frequencies of three alleles of HLA, namely HLA-B*15:02, HLA-C*06:02, and HLA-C*08:01, were significantly higher in the co-trimoxazole-induced SJS/TEN group compared with controls. The risks for co-trimoxazole-induced SJS/TEN in patients with the HLA-B*15:02, HLA-C*06:02, or HLA-C*08:01 allele were about 3-11-fold higher when compared with those who did not carry one of these alleles. Individuals who carried the HLA-B*15:02-C*08:01 haplotype had a 14-fold higher risk for co-trimoxazole-induced SJS/TEN.

CONCLUSION

Evidence of associations between co-trimoxazole-induced SJS/TEN and HLA alleles including HLA-B*15:02, HLA-C*06:02, and HLA-C*08:01 were found in the study population. These findings may suggest that apart from the HLA molecules, other molecules involved in the molecular pathogenesis of these severe cutaneous adverse drug reactions may play an important role in the susceptibility of individuals to SJS/TEN caused by co-trimoxazole.

Variable levels of apoptotic signal-associated cytokines in the disease course of patients with Stevens-Johnson syndrome and toxic epidermal necrolysis

BACKGROUND/OBJECTIVES

Keratinocyte death is a hallmark of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). Apoptotic signal-associated cytokines, such as TNF-α, sFasL, granulysin, sTRAIL and IFN-γ have been reported to participate in keratinocyte apoptosis. However, their levels are variable, which hampers the elucidation of the role of these cytokines. We sought to determine whether cytokine levels vary with disease course.

METHODS

The serum cytokine levels of 24 patients and blister fluid of 10 were analysed by enzyme-linked immunosorbent assay on the first day of their admission to hospital and were evaluated at different time points in the disease course. Meanwhile, surface markers (CD3, CD4, CD8, CD1a, CD14, CD16+56 and CD68) of blister fluid cells were measured by flow cytometry.

RESULTS

The concentrations of all cytokines in the serum and blister fluid were higher than those in the controls and were more elevated in the blister fluid than in the serum. Moreover, sTRAIL, IFN-γ and TNF-α quantities were relatively stable, while those of sFasL and granulysin decreased rapidly in the disease course. On the first day, CD8+ T and natural killer cells were predominant in the blister fluid but their relative percentage diminished gradually, while that of CD14+ cells increased.

CONCLUSION

Our study confirmed there are high but variable levels of these cytokines in SJS/TEN, especially in the early phase and different tendencies are manifested in the disease course.

Cytotoxic Cutaneous Adverse Drug Reactions during Anti-PD-1 Therapy

PURPOSE

Immunotherapy has experienced impressive progress in cancer treatment. Antibodies against PD-1 improved survival in different types of cancer including melanoma. They are generally well tolerated. However, skin toxicities including pruritus, rashes, and vitiligo are reported. Although frequent, they have not been characterized further yet. In this analysis, we aimed to systematically assess and characterize the adverse cutaneous reactions observed in patients with melanoma treated with anti-PD-1 antibodies.

EXPERIMENTAL DESIGN

Patients with melanoma were treated with anti-PD-1 antibodies within clinical trials and an early-access program. Adverse cutaneous eruptions that emerged in our melanoma patient cohort were systematically investigated and classified using histology and gene expression profiling in comparison with maculopapular drug rash, cutaneous GVHD, and the severe drug eruption toxic epidermal necrolysis (TEN).

RESULTS

Between February 2013 and September 2015, 68 patients with stage IV melanoma were treated at the University Hospital Zurich (Zurich, Switzerland); 15 patients (22%) developed cutaneous reactions and 10 (15%) vitiligo. The cutaneous reactions ranged from small erythematous papules with mild pruritus to disseminated erythematous maculopapular rashes (MPR) without signs of epidermal involvement to severe MPRs, including epidermal detachment and mucosal involvement. Although skin involvement varied from mild rash to bullous drug eruptions, gene expression profiling pathogenically classified all investigated cases as TEN-like reactions.

CONCLUSIONS

As predicted by the PD-1 knockout mouse, anti-PD-1 antibodies frequently cause adverse cutaneous reactions. Gene expression profiling reminds in all cases of a TEN-like pattern, suggesting that PD-1/PD-L1 interaction is required to preserve epidermal integrity during inflammatory skin reactions. Clin Cancer Res; 22(16); 4023-9. ©2016 AACR.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: An Update

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening mucocutaneous reactions, predominantly drug induced. The mortality rates for SJS and TEN are as high as 30 %, and short- and long-term morbidities are very common. SJS/TEN is one of the few dermatological diseases that constitute a true medical emergency. Early recognition and prompt and appropriate management can be lifesaving. In recent years, our understanding of the pathogenesis, clinical presentation, and management of SJS/TEN has improved. Nevertheless, in 2015, there are still no internationally accepted management guidelines. This review summarizes up-to-date insights on SJS/TEN and describes a protocol for assessment and treatment. We hope these suggested guidelines serve as a practical clinical tool in the management of SJS/TEN. The classic manifestation of SJS/TEN consists of initial "flu-like" symptoms (malaise, fever, anorexia) in the prodromal phase, followed by cutaneous and mucous membrane (ocular, oral, and genital) inflammation and pain, and other systemic involvement. Symptoms usually begin 4-28 days after the onset of drug intake. Treatment is multidisciplinary and includes identification and withdrawal of the culprit drug, transfer to a specialist unit, supportive care, medical treatment, communication, and provision of appropriate information and emotional support.

Role of Oxidative and Nitrosative Stress in Pathophysiology of Toxic Epidermal Necrolysis and Stevens Johnson Syndrome-A Pilot Study

Background:

Oxidative and nitrosative stress caused by drug metabolism may be a trigger for keratinocyte apoptosis in the epidermis seen in toxic epidermal necrolysis (TEN) and Stevens Johnson syndrome (SJS).

Aims:

To estimate oxidative damage in the serum and to examine the role of nitric oxide in mediating epidermal damage in patients with TEN and SJS.

Materials and Methods:

A prospective study was conducted among TEN and SJS patients and controls in a tertiary care center between January 2006 and February 2010. Patients with a maculopapular drug rash without detachment of skin constituted the control group 1 (drug exposed). Patients without a drug rash constituted the control group 2 (drug unexposed). The serum values of protein carbonyls, malondialdehyde, conjugated diene and nitrates were measured. Two-group comparison with the non-parametric Mann–Whitney U test was used. Significance of differences if any was established using Pearson's Chi-square test.

Results:

Ten patients in the SJS-TEN group (study group), 8 patients in control group 1 and 7 patients in control group 2 were included. More than one drug was implicated in 4/10 patients in group 1 and 3/8 patients in group 2. SCORTEN of 0, 1 and 3 at admission were seen in 2, 6 and 2 patients, respectively. The serum values of protein carbonyls, malondialdehyde, conjugated diene and nitrates were not significantly increased in the study group when compared to the controls.

Conclusions:

There was no elevation of oxidative stress markers in patients with TEN and SJS as compared to the control population.

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis--A Comprehensive Review and Guide to Therapy. I. Systemic Disease

The intent of this review is to comprehensively appraise the state of the art with regard to Stevens Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), with particular attention to the ocular surface complications and their management. SJS and TEN represent two ends of a spectrum of immune-mediated, dermatobullous disease, characterized in the acute phase by a febrile illness followed by skin and mucous membrane necrosis and detachment. The widespread keratinocyte death seen in SJS/TEN is rapid and irreversible, and even with early and aggressive intervention, morbidity is severe and mortality not uncommon. We have divided this review into two parts. Part I summarizes the epidemiology and immunopathogenesis of SJS/TEN and discusses systemic therapy and its possible benefits. We hope this review will help the ophthalmologist better understand the mechanisms of disease in SJS/TEN and enhance their care of patients with this complex and often debilitating disease. Part II (April 2016 issue) will focus on ophthalmic manifestations.

Update on Advances in Research on Idiosyncratic Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major concern for public health, as well as for drug development in the pharmaceutical industry, since it can cause liver failure and lead to drug withdrawal from the market and black box warnings. Thus, it is important to identify biomarkers for early prediction to increase our understanding of mechanisms underlying DILI that will ultimately aid in the exploration of novel therapeutic strategies to prevent or manage DILI. DILI can be subdivided into 'intrinsic' and 'idiosyncratic' categories, although the validity of this classification remains controversial. Idiosyncratic DILI occurs in a minority of susceptible individuals with a prolonged latency, while intrinsic DILI results from drug-induced direct hepatotoxicity over the course of a few days. The rare occurrence of idiosyncratic DILI requires multicenter collaborative investigations and phenotype standardization. Recent progress in research on idiosyncratic DILI is based on key developments in 3 areas: (1) newly developed high-throughput genotyping across the whole genome allowing for the identification of genetic susceptibility markers, (2) new mechanistic concepts on the pathogenesis of DILI revealing a key role of drug-responsive T lymphocytes in the immunological response, and (3) broad multidisciplinary approaches using different platform "-omics" technologies that have identified novel biomarkers for the prediction of DILI. An association of a specific human leukocyte antigen (HLA) allele with DILI has been reported for several drugs. HLA-restricted T-cell immune responses have also been investigated using lymphocytes and T-cell clones isolated from patients. A microRNA, miR-122, has been discovered as a promising biomarker for the early prediction of DILI. In this review, we summarize recent advances in research on idiosyncratic DILI with an understanding of the key role of adaptive immune systems.

Research on Susceptible Genes and Immunological Pathogenesis of Cutaneous Adverse Drug Reactions in Chinese Hans

Cutaneous adverse drug reactions (cADRs) include mild maculopapular exanthems (MPE), Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS) and acute generalized exanthematous pustulosis (AGEP). We used HLA high-resolution genotyping and genome wide association analysis (GWAS) to identify the genetic markers for cADRs induced by common culprit drugs in Han Chinese population. To further understand the immunopathogenesis of cADRs, and with the goal of developing treatment strategies, we compared the expression of cytoxic cytokines between the patients with cADRs and normal controls. Our data suggested that the carbamazepine induced SJS/TEN, allopurinol induced CADRs, methazolamide induced SJS/TEN and SASP induced DRESS were respectively strongly associated with HLA-B*15:02, HLA-B*58:01, HLA-B*59:01 and HLA-B*13:01. In addition, increased expression of cytotoxic cytokines in sera and tissues of cADRs patients were found, compared with healthy controls. Our findings may shed light on prediction and prevention of cADRs, provide clues to pathogenesis, and guide treatment strategies of these reactions.

In vitro diagnosis of delayed-type drug hypersensitivity: mechanistic aspects and unmet needs

Several laboratories use the lymphocyte transformation test for the diagnosis of delayed-type drug hypersensitivity reactions. Recently, the availability of multiple readouts has improved our ability to diagnose reactions. It is important to note that most published studies characterizing the usefulness of diagnostic tests utilize blood samples from well-defined test and control patient groups. The purpose of this article is to briefly summarize the cellular and chemical basis of delayed-type drug hypersensitivity reactions and to review in vitro assays that are available for drug hypersensitivity diagnosis.

The study of severe cutaneous drug hypersensitivity reactions from a systems biology perspective

PURPOSE OF REVIEW

Stevens-Johnson syndrome and toxic epidermal necrolysis are severe hypersensitivity reactions, the majority of which are drug induced. The underlying mechanisms are not fully understood. Here, we review recent findings concerning both mechanistic and genetic factors related to these diseases and propose future approaches to unravel their complexity.

RECENT FINDINGS

Genome-wide association study studies have identified several variants in the human leukocyte antigen region associated with these reactions. These are highly dependent on the population studied and the triggering drug. The T-cell receptor repertoire of the patient is also key. Fas-Fas ligand interactions, perforin and granulysin have also been identified as important players. Furthermore, a high-throughput gene expression study has identified a number of genes that increase in expression in patients during the acute phase of these reactions.

SUMMARY

We review recent high-throughput studies on these diseases and suggest ways in which the data can be combined and reanalyzed using integrative systems biology techniques. We also suggest future lines of research using recent technology that could shed further light on their underlying mechanisms.

An effective strategy to prevent allopurinol-induced hypersensitivity by HLA typing

PURPOSE

This study was conducted to evaluate the usefulness of human leukocyte antigen (HLA) typing in preventing allopurinol-induced severe cutaneous adverse reactions (SCARs) through the application of an allopurinol tolerance induction protocol or prescription of other alternative medications in high-risk patients.

METHODS

HLA typing was performed in patients with chronic renal insufficiency who needed allopurinol. HLA-B*58:01-negative patients were prescribed the usual dose of allopurinol. For HLA-B*58:01-positive patients, administration of either allopurinol based on a 28-day tolerance induction protocol or alternative medications was initiated. Hypersensitivity reactions were surveyed for 90 days and compared with the result of a previous retrospective cohort study.

RESULTS

Among a total of 401 study subjects, no SCARs were noted in HLA-B*58:01-positive patients with application of the tolerance induction protocol (n = 30) or alternative medications (n = 16), nor were any SCARs observed in HLA-B*58:01-negative patients who started allopurinol at the usual dose (n = 355). Compared with the previous retrospective cohort study, a significant reduction in SCARs was observed in HLA-B*58:01-positive patients (0 vs. 18%; P = 0.002).

CONCLUSION

This study shows the usefulness of HLA-B*58:01 screening in identifying patients at high risk for the development of allopurinol-induced SCARs and suggests that application of a tolerance induction protocol or alternative medications could be an effective strategy to prevent allopurinol-induced SCARs in HLA-B*58:01-positive patients.

Localised bullous eruptions and epidermal detachment from the extravasation of hydroxyethyl starch (Voluven)

Extravasation occurs frequently with intravenous infusions. In this case report we describe the occurrence of epidermal detachment and multiple cutaneous bullous eruptions in a patient's forearm following the extravasation of hydroxyethyl starch (Voluven, Fresenius Kabi)-a colloid solution derived from corn starch, which is used to replace lost blood volume. The patient's affected body surface area was managed under the direction of our plastic surgical team. Despite a prolonged admission in hospital from other perioperative complications, he made a full recovery and was successfully discharged home. The probable pathogenesis relevant to extravasation of Voluven is discussed; as well as its management principles.

Stevens-Johnson Syndrome and toxic epidermal necrolysis: a multi-aspect comparative 7-year study from the People's Republic of China

Background

Stevens–Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but severe cutaneous drug reactions. They are differentiated based on the fraction of the body surface area affected. Optimal therapy for SJS and TEN is a controversial issue.

Objective

We compared the treatments given to and the clinical outcomes of 39 cases of SJS and 48 cases of TEN seen at a single institution between January 2007 and December 2013 for better understanding of the clinical characteristics and development of the two conditions.

Methods

Demographic data, clinical characteristics, treatments given, and therapeutic responses observed were retrospectively collected.

Results

The incidence rates of hypoproteinemia and secondary infections are significantly higher in TEN than in SJS (P=0.001 and P=0.002, respectively). The corticosteroid dose did not influence the time from the initiation of therapy to control of the lesions in SJS, but increasing the dosage of corticosteroids progressively decreased the time from the initiation of therapy to control of the lesions in TEN. With increases in the utilization ratio of intravenous immunoglobulin (IVIG), the length of the hospital stay became shorter, whereas the time from the initiation of therapy to control of the lesions remained the same in SJS. However, for TEN, both the length of the hospital stay and the time from the initiation of therapy to control of the lesions became shorter with increases in the utilization ratio of IVIG.

Conclusion

SJS and TEN are two variants of the same spectrum, and they differ from each other not only in the severity of epidermal detachment but also in other clinical parameters and their distinct clinical courses. Thus, differential treatment of both conditions may have benefits for their prognosis.

Immunological response in Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous adverse drug reactions that induce widespread epidermal necrosis. Recent advances in pharmacogenomic studies have provided evidence of genetic predispositions to SJS/TEN. Several concepts have been proposed to explain the pathogenesis of severe cutaneous adverse drug reactions. In the hapten concept, small molecules called haptens elicit an immune response only when attached to proteins. The "p-i" concept postulates that the causative drugs can stimulate cells by binding directly and reversibly to immune receptors. In addition, there is the idea that drugs alter the antigen by binding to the human leukocyte antigen pocket. With regard to keratinocyte death, several cell death mediators, such as FasL, granulysin and annexin A1, have been proposed as playing a role in SJS/TEN pathogenesis. A subset of T lymphocytes, including regulatory T cells, also may play a role in SJS/TEN.

HLA-B∗ 1502 is associated with carbamazepine induced Stevens-Johnson syndrome in North Indian population

The evidence of association between HLA-B(∗)1502 and anticonvulsant induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) from the Indian population is scant. Patients with a history of SJS/TEN secondary to carbamazepine or phenytoin were enrolled. The control group comprised of patients who had received carbamazepine/phenytoin for ⩾ 6 months without any adverse cutaneous event. Low-resolution DNA typing for HLA-B and high resolution HLA-B(∗)15 typing was performed. Seventeen patients with history of SJS/TEN secondary to carbamazepine (9) or phenytoin (8) and 50 tolerant controls (carbamazepine-37; phenytoin-13) were enrolled. The mean age of patients and controls was 33.9 ± 11.6 and 28.1 ± 9.9 years, respectively. HLA-B(∗)1502 was observed in 2/9 (22.2%) carbamazepine-SJS/TEN patients and none of the 37 carbamazepine tolerant controls (p = 0.035). HLA-B(∗)1502 was not observed in any of the 8 phenytoin-SJS/TEN patients or the 13 phenytoin tolerant controls. Our data suggests that HLA-B(∗)1502 is a risk factor for carbamazepine induced SJS/TEN. Therefore, HLA-B(∗)1502 testing should be performed prior to initiating carbamazepine in North Indian population.

High-Dose Intravenous Immunoglobulins in the Treatment of Toxic Epidermal Necrolysis: An Asian Series

Toxic epidermal necrolysis (TEN) is a severe, immune-mediated, mucocutaneous reaction resulting in extensive keratinocyte apoptosis. High-dose human intravenous immunoglobulins (IVIG) have been proposed as an effective treatment for TEN. Retrospective data from 8 patients with TEN and 4 patients with Stevens-Johnson syndrome-toxic epidermal necrolysis (SJS-TEN) overlap treated with high-dose IVIG were analysed. The total dose of IVIG administered was 2 g/kg body weight, with the exception of 2 patients who received a total dose of 1.5 g/kg body weight. Their mean age was 49.9+/-18.8 years (range, 19 to 70 years). The mean time from the first sign of skin lesion or mucosal or epidermal detachment to commencement of IVIG was 8.7+/-5.5 days (range, 3 to 22 days). Of the 11 patients who survived, the mean time to objective response was 3.6+/-1.9 days (range, 2 to 8 days). The length of stay (LOS) in hospital was 20.4+/-8.0 days (range, 10 to 37 days). The survival rate was 91.6%. One patient developed permanent mucocutaneous sequelae following TEN. There were no adverse reactions to IVIG. We conclude that high-dose IVIG may be a safe and effective therapy for Asian patients with TEN.

Erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis: a comparative review

BACKGROUND

Human erythema multiforme (EM) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are separate conditions. There is no consensus on classification criteria for the eponymous diseases in animals.

RESULTS

Animal EM is very different from 90% of human EM, which is herpes virus associated (HAEM). Animals lack acrally distributed, typical raised targets. Unlike canine parvovirus 'EM', HAEM is not an active infection. Animal EM is often attributed to drugs, but this is rarely proved. Conversely, human and animal SJS/TEN are almost identical, life-threatening disorders of epidermal necrosis and detachment, typically triggered by drugs (occasionally by infectious agents). Both EM and SJS/TEN are mediated by cytotoxic lymphocyte responses against altered keratinocytes (infectious agents or drugs). Apoptosis results from direct cytotoxicity or through soluble mediators, namely Fas ligand, granzymes, perforin and granulysin. Diagnosis in humans is clinicopathological, with emphasis on clinical lesions; histopathology confirms the pathological process as interface (cytotoxic) dermatitis. Human EM is self-limiting; only recurrent and rare persistent cases require antiviral/immunosuppressive therapies. Drug-induced EM responds to drug withdrawal. Idiopathic canine EM (>40%) is usually chronic, refractory to treatment and may represent heterogeneous conditions. Early identification and removal of the causative drug and high-quality supportive care are critical in SJS/TEN. Mortality rate is nevertheless high.

CONCLUSIONS AND CLINICAL IMPORTANCE

(1) Histopathological lesions do not reliably differentiate EM, SJS and TEN. (2) A multicentre study to develop a consensus set of clinical criteria for EM and SJS/TEN in animals is overdue. (3) No adjunctive therapies, including intravenous immunoglobulin and ciclosporin, have met evidence-based standards.

Negative regulation by PD-L1 during drug-specific priming of IL-22-secreting T cells and the influence of PD-1 on effector T cell function

Activation of PD-1 on T cells is thought to inhibit Ag-specific T cell priming and regulate T cell differentiation. Thus, we sought to measure the drug-specific activation of naive T cells after perturbation of PD-L1/2/PD-1 binding and investigate whether PD-1 signaling influences the differentiation of T cells. Priming of naive CD4(+) and CD8(+) T cells against drug Ags was found to be more effective when PD-L1 signaling was blocked. Upon restimulation, T cells proliferated more vigorously and secreted increased levels of IFN-γ, IL-13, and IL-22 but not IL-17. Naive T cells expressed low levels of PD-1; however, a transient increase in PD-1 expression was observed during drug-specific T cell priming. Next, drug-specific responses from in vitro primed T cell clones and clones from hypersensitive patients were measured and correlated with PD-1 expression. All clones were found to secrete IFN-γ, IL-5, and IL-13. More detailed analysis revealed two different cytokine signatures. Clones secreted either FasL/IL-22 or granzyme B. The FasL/IL-22-secreting clones expressed the skin-homing receptors CCR4, CCR10, and CLA and migrated in response to CCL17/CCL27. PD-1 was stably expressed at different levels on clones; however, PD-1 expression did not correlate with the strength of the Ag-specific proliferative response or the secretion of cytokines/cytolytic molecules. This study shows that PD-L1/PD-1 binding negatively regulates the priming of drug-specific T cells. ELISPOT analysis uncovered an Ag-specific FasL/IL-22-secreting T cell subset with skin-homing properties.

Cytotoxic proteins and therapeutic targets in severe cutaneous adverse reactions

Severe cutaneous adverse reactions (SCARs), such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN), are rare but life-threatening conditions induced mainly by a variety of drugs. Until now, an effective treatment for SJS/TEN still remains unavailable. Current studies have suggested that the pathobiology of drug-mediated SJS and TEN involves major histocompatibility class (MHC) I-restricted activation of cytotoxic T lymphocytes (CTLs) response. This CTLs response requires several cytotoxic signals or mediators, including granulysin, perforin/granzyme B, and Fas/Fas ligand, to trigger extensive keratinocyte death. In this article, we will discuss the cytotoxic mechanisms of severe cutaneous adverse reactions and their potential applications on therapeutics for this disease.

Generalized bullous fixed drug eruption is distinct from Stevens-Johnson syndrome/toxic epidermal necrolysis by immunohistopathological features

BACKGROUND

Generalized bullous fixed drug eruption (GBFDE), a particular form of fixed drug eruption (FDE), is characterized by widespread blisters and erosions and can be confused with Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).

OBJECTIVE

We sought to analyze specific features of GBFDE and differentiate it from SJS/TEN.

METHODS

We retrospectively studied patients with GBFDE and SJS/TEN during a period of 10 years. GBFDE was defined as typical FDE lesions with blisters involving at least 10% body surface area on at least 3 of 6 different anatomic sites. Clinical presentations; histopathological features; immunohistochemical patterns of cluster-of-differentiation (CD)3, CD4, CD8, CD56, Fas, Fas ligand, granzyme B, perforin, granulysin, and forkhead box P3 (Foxp3); and serum granulysin levels were compared.

RESULTS

Twenty-three cases of GBFDE were collected. Patients with GBFDE had shorter latent periods, less mucosal involvement, more eosinophil infiltration, and dermal melanophages. Lesional infiltrates in GBFDE had more dermal CD4(+) cells including Foxp3(+) regulatory T cells, fewer intraepidermal CD56(+) cells, and fewer intraepidermal granulysin(+) cells. The serum level of granulysin in GBFDE was also significantly lower than in SJS/TEN.

LIMITATIONS

The number of cases in this study is small.

CONCLUSION

GBFDE is a distinct disease distinguishable from SJS/TEN by particular features such as granulysin, CD56, and Foxp3 expressions.

T cell responses to drugs and drug metabolites

Understanding the chemical mechanisms by which drugs and drug metabolites interact with cells of the immune system is pivotal to our knowledge of drug hypersensitivity as a whole.In this chapter, we will discuss the currently accepted mechanisms where there is scientific and clinical evidence to support the ways in which drugs and their metabolites interact with T cells. We will also discuss bioanalytical platforms, such as mass spectrometry, and in vitro test assays such as the lymphocyte transformation test that can be used to study drug hypersensitivity; the combination of such techniques can be used to relate the chemistry of drug antigen formation to immune function. Ab initio T cell priming assays are also discussed with respect to predicting the potential of a drug to cause hypersensitivity reactions in humans in relation to the chemistry of the drug and its ability to form haptens, antigens and immunogens in patients.

Effect of age and early intervention with a systemic steroid, intravenous immunoglobulin or amniotic membrane transplantation on the ocular outcomes of patients with Stevens-Johnson syndrome

PURPOSE

This retrospective observational case series of fifty-one consecutive patients referred to the eye clinic with acute-stage Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) from 1995 to 2011 examines the effect of early treatment with a systemic corticosteroid or intravenous immunoglobulin (IVIG) on the ocular outcomes in patients with SJS or TEN.

METHODS

All patients were classified by age (≤18 years vs. >18 years) and analyzed by treatment modality and early intervention with systemic corticosteroids (≤5 days), IVIG (≤6 days), or amniotic membrane graft transplantation (AMT) (≤15 days). The main outcomes were best-corrected visual acuity (BCVA) in logarithm of the minimum angle of resolution (logMAR) and ocular involvement scores (OIS, 0-12), which were calculated based on the presence of superficial punctate keratitis, epithelial defect, conjunctivalization, neovascularization, corneal opacity, keratinization, hyperemia, symblepharon, trichiasis, mucocutaneous junction involvement, meibomian gland involvement, and punctal damage.

RESULTS

The mean logMAR and OIS scores at the initial visit were not significantly different in the pediatric group (logMAR = 0.44, OIS = 2.76, n = 17) or the adult group (logMAR = 0.60, OIS = 2.21, n = 34). At the final follow-up, the logMAR and OIS had improved significantly in the adult group (p = 0.0002, p = 0.023, respectively), but not in the pediatric group. Early intervention with IVIG or corticosteroids significantly improved the mean BCVA and OIS in the adult group (p = 0.043 and p = 0.024, respectively for IVIG; p = 0.002 and p = 0.034, respectively for corticosteroid). AMT was found to be associated with a significantly improved BCVA or OIS in the late treatment group or the group with a better initial OIS (p = 0.043 and p = 0.043, respectively for BCVA; p = 0.042 and p = 0.041, respectively for OIS).

CONCLUSIONS

Our findings suggest that patients with SJS or TEN who are aged 18 years or less have poorer ocular outcomes than older patients and that early treatment with steroid or immunoglobulin therapy improves ocular outcomes.

Clinical Pharmacogenetics Implementation Consortium guidelines for HLA-B genotype and carbamazepine dosing

Human leukocyte antigen B (HLA-B) is a gene that encodes a cell surface protein involved in presenting antigens to the immune system. The variant allele HLA-B*15:02 is associated with an increased risk of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in response to carbamazepine treatment. We summarize evidence from the published literature supporting this association and provide recommendations for the use of carbamazepine based on HLA-B genotype (also available on PharmGKB: http://www.pharmgkb.org). The purpose of this article is to provide information to allow the interpretation of clinical HLA-B*15:02 genotype tests so that the results can be used to guide the use of carbamazepine. The guideline provides recommendations for the use of carbamazepine when HLA-B*15:02 genotype results are available. Detailed guidelines regarding the selection of alternative therapies, the use of phenotypic tests, when to conduct genotype testing, and cost-effectiveness analyses are beyond the scope of this document. Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines are published and updated periodically on the PharmGKB website at (http://www.pharmgkb.org).

Human leukocyte antigen-associated drug hypersensitivity

A growing number of associations between adverse drug reactions and alleles of the human leukocyte antigen (HLA) genes are now known. Although several models have been proposed to explain these associations, an underlying molecular basis has only recently been described. The associations between HLA-B*57:01 and abacavir hypersensitivity syndrome, and HLA-B*15:02 and carbamazepine-induced bullous skin disease have provided new insights into the mechanism associated with hypersensitivity reactions to these drugs. Here we discuss recent evidence that small molecules can interact with specific HLA to distort self-peptide presentation leading to autoimmune-like drug hypersensitivities that potentially provide clues to the mechanisms underlying other immunopathologies.

Immunological mechanisms of epidermal damage in toxic epidermal necrolysis

PURPOSE OF REVIEW

The purpose of the present review is to introduce recent findings on the pathomechanisms of toxic epidermal necrolysis (TEN), which is characterized by widespread epidermal detachment due to keratinocyte apoptosis.

RECENT FINDINGS

In the mechanism of epidermal damage, the roles of drug metabolites, cytotoxic lymphocytes, and apoptosis-inducing factors have been noted. In addition, recent studies have focused on monocytes/macrophages, which may participate in epidermal damage through the production of apoptosis-inducing factors and the expression of costimulatory factors with the ability to activate CD8 T cells.

SUMMARY

Epidermal keratinocyte death is a hallmark of TEN. In a very high proportion of cases, drugs are responsible for TEN. It has been suggested that toxic drug metabolites produced by keratinocytes act like electrophilic agents to induce apoptosis and inflammation. Next, cytotoxic lymphocytes and monocytes function in the development of widespread epidermal damage through direct or indirect cytotoxic pathways. In addition, T-cell activation may be strengthened by the impairment of regulatory T-cell function and activated monocytes. The development of epidermal damage in TEN may require the coordinated action of these factors.

Recovered patients with Stevens-Johson syndrome and toxic epidermal necrolysis maintain long-lived IFN-γ and sFasL memory response

There is evidence that drug-specific T cells are involved in inducing keratinocyte apoptosis in acute stage of Steven-Johson syndrome (SJS) and Toxic epidermal necrolysis (TEN). However, there are few studies that have attempted to examine T cell memory responses over time. We sought to determine the duration of IFN-γ and sFasL memory response to causal drugs in patients with SJS and TEN after remission. Eight patients with previous SJS and TEN were enrolled. Memory T cells were measured by 10-day cultured IFN-γ enzyme-linked immunosorbent spot-forming cell (ELISpot) assay. Effector T-cell responses were measured by ex vivo IFN-γ ELISpot assay and sFasL ELISA. The sFasL-mediated toxicities of drug-stimulated PBMC supernatants against keratinocyte line were further investigated by MTT proliferation assay and Annexin-V staining. We observed significant cultured and ex vivo IFN-γ ELISpot responses against causal drugs in all 8 patients. In addition, the sFasL levels were specifically increased in the supernatant of PBMCs cultured with causal drugs from 6 of 8 patients. Drug-stimulated PBMC supernatants were cytotoxic against keratinocyte line, which was inhibited by anti-FasL mAb in a dose-dependent manner. Our findings confirmed that drug-specific IFN-γ and sFasL memory response against causal drugs could be sustained over several years and further suggest that patients should avoid causal drug re-exposure after the recovery of TEN and SJS.

Drug allergy: causes and desensitization

Allergic drug reactions occur when a drug, usually a low molecular weight molecule, has the ability to stimulate an immune response. This can be done in one of two ways. The first is by binding covalently to a self-protein, to produce a haptenated molecule that can be processed and presented to the adaptive immune system to induce an immune response. Sometimes the drug itself cannot do this but a reactive breakdown product of the drug is able to bind covalently to the requisite self-protein or peptide. The second way in which drugs can stimulate an immune response is by binding non-covalently to antigen presenting or antigen recognition molecules such as the major histocompatibility complex (MHC) or the T cell receptor. This is known as the p-I or pharmacological interaction hypothesis. The drug binding in this situation is reversible and stimulation of the response may occur on first exposure, not requiring previous sensitization. There is probably a dependence on the presence of certain MHC alleles and T cell receptor structures for this type of reaction to occur.

Recent advances in the genetics and immunology of Stevens-Johnson syndrome and toxic epidermal necrosis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrosis (TEN) are rare but life-threatening severe cutaneous adverse reactions (SCARs), which are majorly (65-75%) induced by a variety of drugs. SJS/TEN could be recognized as SCARs or drug immune reactions, if the reactions are elicited by drugs. The recent studies suggested that SJS/TEN is a specific immune reaction initiated by the cytotoxic T lymphocytes (CTLs) via human leukocyte antigens (HLAs)-restricted pathway. The patho-mechanism involving HLA-restricted presentation of a drug or its metabolites for T-cell activation is supported by the findings of strong genetic associations with HLA alleles (e.g. HLA-B*15:02 and carbamazepine-SJS/TEN, and HLA-B*58:01 and allopurinol-SJS/TEN). However, the genetic associations of SJS/TEN or drug induced cutaneous immune reactions are complex, which are drug specific and ethnicity specific. The genetic polymorphisms and diversity of HLA alleles may provide different binding affinities for drug antigens to launch the activation of specific CTLs responses, further leading to the unique clinical manifestations in SJS/TEN. Fas-FasL and perforin/granzyme B have been advocated mediating the epidermal necrosis in SJS/TEN. Our recent study showed that granulysin, a cytotoxic protein produced by CTLs or natural killer (NK) cells, is the key mediator for disseminated keratinocyte death in SJS/TEN. From the point of view of a physician, the profounder understanding of the genetic predisposition and patho-mechanism we discover, the better strategies for prevention, clinical management, and therapeutic methods of SJS/TEN we can develop in the near future.

Necrólisis epidérmica tóxica en paciente infectado por virus de inmunodeficiencia humana

Introducción: Necrólisis Epidérmica Tóxica es un trastorno multifactorial, en el cual participan, infecciones virales, interacciones medicamentosas, y donde la carga genética cumple un papel importante en la susceptibilidad a las reacciones adversas. Con la presentación de este artículo se quiere exponer el reporte de un caso de una enfermedad poco común en el ámbito médico, pero la cual tiene un alto índice de morbimortalidad, y secuelas. En pacientes con coinfección con el virus de la inmunodeficiencia humana se aumenta 1000 el riesgo de padecerla. Presentamos un paciente masculino de 32 años, con antecedentes de síndrome convulsivo en manejo con fenobarbital y fenitoína, en coinfección por virus de inmunodeficiencia humana de diagnóstico reciente, sin niveles de CD4, ni carga viral y sin manejo antirretroviral, quien presenta ingestión de ciprofloxacino 12 días antes del inicio de cuadro clínico el cual es consistente con fiebre elevada, lesiones vesiculosas de fondo eritematoso, confluentes, observándose flictenas en pared anterior tórax de contenido seroso, con desprendimiento de la epidermis al ejercer una suave presión sobre la piel afectada dejando áreas húmedas, rojas, Nikolsky positivo,  cuya extensión de las lesiones comprometen el 91% de su superficie corporal total, acompañada además de prurito de moderada intensidad. Durante la estancia hospitalaria se realiza manejo terapéutico con ciclosporina A, e inmunoglobulina G específica humana, cubrimiento antibiótico y antimicótico con evolución satisfactoria del estado hemodinámico del paciente y las lesiones en piel.  [Escalante E, Oliva J, Paez E. Necrólisis epidérmica tóxica en paciente infectado por virus de inmunodeficiencia humana. Reporte de un caso. MedUNAB 2012;15(1):68-72].

Covalent binding of nitroso-sulfonamides to glutathione S-transferase in guinea pigs with delayed type hypersensitivity

Drug induced allergies are believed to be induced by conjugates consisting of biological macromolecules and active metabolites. The present study investigated whether guinea pig glutathione S-transferase (gpGST), a protein that binds with sulfanilamide (SA) and sulfamethoxazole (SMX), could be detected in the liver cytosol fraction of guinea pigs that intraperitoneally received SA or SMX, and whether gpGST is a carrier protein. We synthesized three nitroso compounds, i.e., 4-nitroso-sulfanilamide (SA-NO), 4-nitrososulfamethoxazole (SMX-NO) and fluorescent-labeled nitroso compound (DNSBA-NO), and examined binding quantities of nitroso compounds to gpGST purified from untreated female guinea pigs. Furthermore, the concentrations of IgG in serum antibody for nitroso compounds were estimated using ELISA. When guinea pigs were sensitized using the three nitroso compounds, the dose dependent skin reactions were confirmed with each compound. In addition, sensitized guinea pigs using each nitroso compound showed positive skin reactions at an elicitation test performed using gpGST alone. The results confirmed synthesis of antibody against gpGST due to hapten sensitization. Therefore, when a nitroso compound binds with gpGST in the body of guinea pigs, nitroso-gpGST acts as a neoantigen, which induces synthesis of autoantibody. Thus, gpGST appears to be one of the carrier proteins that induce sulfa drug-induced allergies. Immunization of guinea pigs with active metabolite of drugs may give information for predicting the occurrence of delayed type hypersensitivity in human.